1. Technical Field
This invention relates generally to dynamic radial shaft seals, and more particularly to dynamic radial shaft seals having axially extending dust exclusion lips and thrust pads.
2. Related Art
Dynamic radial shaft seals often include an annular outer seal component and an annular inner seal component. The outer seal component is configured to be mounted in a housing about an opening to be sealed and the inner seal component, including a wear sleeve, is configured to be mounted on and rotateable with a shaft extending through the opening. The outer seal component typically includes an outer metal case having a metal cylindrical portion sized for press fit into the housing with a leg extending radially inwardly from the cylindrical portion. Further, an elastomeric body is typically attached to the leg, with a main seal lip of the elastomeric body extending radially inwardly from an end of the leg to abut and provide a seal against a cylindrical running surface of the wear sleeve. Further, the elastomeric body typically includes one or more dust exclusion lips to prevent dust and other contamination from reaching and by-passing the main seal lip. The dust exclusion lips can be configured to ride against the cylindrical running surface of the wear sleeve and also to ride against a flange of the wear sleeve that extends radially outwardly from the wear sleeve cylindrical running surface. In addition to the main seal lip and the dust exclusion lips, it is known to provide a separate thrust pad between the leg of the metal case and the flange of the wear sleeve. Typically, the thrust pad is oriented radially outwardly from one or more of the dust exclusion lips. As such, the radial envelope of the seal assembly is necessarily increased to accommodate the thrust pad, or one or more of the dust exclusion lips are removed, which in turn, reduces the potential to inhibit the ingress of dust and other contamination.